Merge remote-tracking branch 'Knectar/dev' into dev

src/extras/geometries/OctahedronGeometry.js

@@ -0,0 +1,138 @@
+/**
+ * Octahedrons have 8 sides. This octahedron supports subdivision.
+ * 
+ * Vertices have 'smooth' normals, 
+ * to make a sharp edge choose a material that uses face normals instead.
+ *
+ * @author daniel.deady@knectar.com
+ * @param radius
+ * @param detail Final number of triangles = 4^detail * 8
+ */
+
+THREE.OctahedronGeometry = function ( radius, detail ) {
+
+	THREE.Geometry.call( this );
+
+	detail = isFinite(detail) ? detail : 3; // allow a zero value
+
+	var that = this; // ugly scope hack
+
+	prepare( new THREE.Vector3( +1, 0, 0 ) ); // right
+	prepare( new THREE.Vector3( -1, 0, 0 ) ); // left
+	prepare( new THREE.Vector3( 0, +1, 0 ) ); // up
+	prepare( new THREE.Vector3( 0, -1, 0 ) ); // down
+	prepare( new THREE.Vector3( 0, 0, +1 ) ); // front
+	prepare( new THREE.Vector3( 0, 0, -1 ) ); // back
+	var midpoints = [], p = this.vertices;
+
+	// careful to output faces counter-clockwise, that is required for meshes
+	make( p[0], p[2], p[4], detail );
+	make( p[0], p[4], p[3], detail );
+	make( p[0], p[3], p[5], detail );
+	make( p[0], p[5], p[2], detail );
+	make( p[1], p[2], p[5], detail );
+	make( p[1], p[5], p[3], detail );
+	make( p[1], p[3], p[4], detail );
+	make( p[1], p[4], p[2], detail );
+
+	/**
+	 * Project vector onto sphere's surface
+	 */
+	function prepare( vector ) {
+
+		var normal = vector.clone().normalize();
+		var vertex = new THREE.Vertex( normal.clone().multiplyScalar( radius ) );
+		vertex.index = that.vertices.push( vertex ) - 1;
+
+		// Texture coords are equivalent to map coords, calculate angle and convert to fraction of a circle.
+		var u = azimuth( vector ) / 2 / Math.PI + 0.5;
+		var v = inclination( vector ) / Math.PI + 0.5;
+		vertex.uv = new THREE.UV( u, v );
+
+		return vertex;
+
+	}
+
+	/**
+	 * Approximate a curved face with recursively sub-divided triangles.
+	 */
+	function make( v1, v2, v3, detail ) {
+
+		if ( detail < 1 ) {
+
+			var face = new THREE.Face3( v1.index, v2.index, v3.index, [ v1.position, v2.position, v3.position ] );
+			face.centroid.addSelf( v1.position ).addSelf( v2.position ).addSelf( v3.position ).divideScalar( 3 );
+			face.normal = face.centroid.clone().normalize();
+			that.faces.push( face );
+
+			var azi = azimuth( face.centroid );
+			that.faceVertexUvs[ 0 ].push( [ 
+				correctUV( v1.uv, v1.position, azi ),
+				correctUV( v2.uv, v2.position, azi ),
+				correctUV( v3.uv, v3.position, azi )
+			] );
+
+		}
+		else {
+
+			detail -= 1;
+			// split triangle into 4 smaller triangles
+			make( v1, midpoint( v1, v2 ), midpoint( v1, v3 ), detail ); // top quadrant
+			make( midpoint( v1, v2 ), v2, midpoint( v2, v3 ), detail ); // left quadrant
+			make( midpoint( v1, v3 ), midpoint( v2, v3 ), v3, detail ); // right quadrant
+			make( midpoint( v1, v2 ), midpoint( v2, v3 ), midpoint( v1, v3 ), detail ); // center quadrant
+
+		}
+
+	}
+
+	function midpoint( v1, v2 ) {
+
+		if ( !midpoints[ v1.index ] ) midpoints[ v1.index ] = [];
+		if ( !midpoints[ v2.index ] ) midpoints[ v2.index ] = [];
+		var mid = midpoints[ v1.index ][ v2.index ];
+		if ( mid === undefined ) {
+			// generate mean point and project to surface with prepare()
+			midpoints[ v1.index ][ v2.index ] = midpoints[ v2.index ][ v1.index ] = mid = prepare( 
+				new THREE.Vector3().add( v1.position, v2.position ).divideScalar( 2 ) 
+			);
+		}
+		return mid;
+
+	}
+
+	/**
+	 * Angle around the Y axis, counter-clockwise when looking from above.
+	 */
+	function azimuth( vector ) {
+
+		return Math.atan2( vector.z, -vector.x );
+
+	}
+
+	/**
+	 * Angle above the XZ plane.
+	 */
+	function inclination( vector ) {
+
+		return Math.atan2( -vector.y, Math.sqrt( ( vector.x * vector.x ) + ( vector.z * vector.z ) ) );
+
+	}
+
+	/**
+	 * Texture fixing helper. Spheres have some odd behaviours.
+	 */
+	function correctUV( uv, vector, azimuth ) {
+
+		if ( (azimuth < 0) && (uv.u === 1) ) uv = new THREE.UV( uv.u - 1, uv.v );
+		if ( (vector.x === 0) && (vector.z === 0) ) uv = new THREE.UV( azimuth / 2 / Math.PI + 0.5, uv.v );
+		return uv;
+
+	}
+
+	this.boundingSphere = { radius: radius };
+
+};
+
+THREE.OctahedronGeometry.prototype = new THREE.Geometry();
+THREE.OctahedronGeometry.prototype.constructor = THREE.OctahedronGeometry;

utils/build.py

@@ -104,6 +104,7 @@ EXTRAS_FILES = [
 'extras/geometries/ExtrudeGeometry.js',
 'extras/geometries/IcosahedronGeometry.js',
 'extras/geometries/LatheGeometry.js',
+'extras/geometries/OctahedronGeometry.js',
 'extras/geometries/PlaneGeometry.js',
 'extras/geometries/SphereGeometry.js',
 'extras/geometries/TextGeometry.js',